The present invention relates to a fermentation vat, in particular to an automatic type of vat for making red wine, which includes a main vat, an upper vat over the main vat, an uplift pipe for drawing fermenting liquid from the bottom of the main vat to the upper vat, means for releasing this liquid from the upper vat to the main vat so as to spray the layer of grape marc floating in the main vat and injector means, associated with the uplift pipe, for injecting into the liquid flowing through this pipe a flow of gas containing a suitable proportion of oxygen to oxygenate it.
During fermentation, and especially when making red wine, it is known that the must has to be oxygenated at various predetermined stages of fermentation. In particular, when making red wine, oxygenation helps metabolize yeasts since it makes it easier for fermentation to get under way, by increasing the growth of microbial flor and also prevents fermentation from stopping too early. In addition, oxygenating the must encourages condensation reactions between tannins and anthocians, thereby producing more complex molecules which make the colour more stable. Oxygenation also prevents the formation of unwelcome reduction agents and encourages the development of varietal aromas.
Patent Application TO97A000749, in the name of the present Applicant, describes a fermentation vat of the type described above, in which the must is oxygenated by aspirating ambient air and mixing it into the liquid flowing through the uplift pipe; in particular, the uplift pipe collects liquid from the bottom region of the main vat and conveys it, by means of a pump, to the upper vat, from where the oxygenated liquid is periodically released back into the main vat through a valve in the bottom of the upper vat which, when open, causes the liquid to be sprayed onto a cap of marc floating on the must/wine in the main vat.
The object of the present invention is to perfect the fermentation vat of the type described above, in order to achieve better fermentation process.
This object is achieved by providing a fermentation vat having the characteristics claimed in the introduction to the present description, characterised in that the aforesaid uplift pipe has a first outflow aperture feeding the liquid into the upper vat and a second outflow aperture feeding the liquid into the mass of liquid contained in the main vat, valve means being provided, in association with the uplift pipe, for selectively feeding the liquid into the upper vat or into the main vat, or into both, through the said outflow apertures.
Thanks to the above characteristics it is possible, at predetermined stages of the fermentation process, selectively to direct the flow of oxygenated liquid into the upper vat, and then to spray the cap of marc or, alternatively, to convey this liquid into the heart of the liquid contained in the main vat, thereby oxygenating it better and also achieving other advantages which will become apparent from the detailed description which follows.